Yeah, a good dual plane intake would be a better choice for street driving, and an occasional romp at the track. I run 3.55's and I like them. It all depends on your intent, if it's mostly street 3.55's with a suregrip and a good converter built to your car would be a fun little package.
As far as cam choices I'm sure there will be plenty of recommendations, I'm still fuzzy in that area myself. I know just enough to get myself in trouble, lol. But like I said, the thing to keep in mind is the retainer to valve guide clearance/coil bind and the piston to valve clearance. The more aggressive you go, the more machining (expense) will be needed. I'm not sure on the Magnums, but I know the LA it's safe to around .500 lift before you need to start worrying in most cases.
Then you have the whole power brake issue, a cam that won't provide enough vacuum will decrease the boosters ability to assist, there are ways around that, either go manual or add a boost assist.
